In the prior art, fluid systems are provided in which a high pressure stream of water, i.e., at pressures of 6 to 10,000 pounds or more, are used for many cleaning applications. In some of these systems one or more hand-held valve assemblies or guns are provided, and are connected by a hose to a common outlet of a pump. The guns generally include a housing having a valve therein, a barrel extension for directing the high pressure stream of water through a nozzle to the object to be cleaned, a handle or trigger mechanism for operating the valve, and a relatively unrestricted pressure relief or "dump" outlet for relieving pressure in the assembly when flow through the high pressure nozzle outlet is interrupted by operation of the valve.
In some applications it is desired to have a vertically suspended mechanism. These contain an inlet, a housing rotatably journaled thereon and an internal chamber which passes through a non-rotating portion of the housing and through a rotating portion of the housing leading to one or more outlets in the form of nozzles which provide a high pressure generally downwardly directed spray for cleaning a surface or object. The inlet is connected through suitable hosing or piping to a source of highly pressurized fluid which is usually water and/or water containing detergents or other cleaning agents. In order to avoid spot treatment and promote uniformity the outlet nozzles are generally slightly angled off the vertical axis of the device which through reaction forces creates a turning moment which causes the rotatable element to rotate in response to the reaction forces generated when the fluid is flowing.
A problem is encountered because on the one hand it is desirable to have minimum friction in the rotatable element so as to permit the rotation of the part of the housing containing the outlet nozzles in order to maintain the spray in a generally downward direction without excessive angulation off the vertical, and yet provides sufficient friction so that the rotatable element does not overrotate and turn at excessive speeds. The reaction forces are difficult to estimate and it is difficult to balance the combination of frictional forces and reaction forces so that the rotatable portion of the housing containing the nozzles will rotate but will not overrotate at a excessively high speed.
It was discovered that the incorporation of a specially constructed magnetic rotor assembly on the rotatable spindle prevents the rotating mechanism from accelerating to an undesirably high speed but does not otherwise effect the operation. The magnetic rotor assembly includes permanent magnets which do not require the use of a battery.